Sara Krueger, who was detained at a San Francisco Bay Area commuter train station along with Ryan Scott Warner on Feb. 2nd in El Cerrito. The couple was wanted for questioning in the death of Krueger's 3-year-old daughter.

Photo: Associated Press

Sara Krueger, who was detained at a San Francisco Bay Area commuter...

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This image provided by the Napa Police department shows Ryan Scott Warner, who was detained at a San Francisco Bay Area commuter train station along with Sara Krueger Sunday Feb. 2, 2014 in the city of El Cerrito. The couple was wanted for questioning in the death of Krueger's 3-year-old daughter.

Photo: Associated Press

This image provided by the Napa Police department shows Ryan Scott...

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Pictures of Kayleigh Slusher sit among stuffed animals and candles to memorialize the 3-years old little girl, outside the apartment building where her body of was found dead in Napa. The girl’s mother Sara Krueger and her boyfriend Ryan Scott Warner have been arrested on suspicion of special circumstances murder and assault in connection with the killing.

Pictures of Kayleigh Slusher sit among stuffed animals and candles...

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Savannah Fanjul thinks about her step-sister Kayleigh Slusher, Monday February 3, 2014, as she sits on the steps at the memorial outside the apartment building in Napa, Calif. Three year old Kayleigh Slusher was found dead, Saturday in her bed. The mother Sara Krueger and her boyfriend Ryan Scott Warner have been arrested on suspicion of murder and assault in connection with the killing of Kayleigh.

Photo: Lacy Atkins, The Chronicle

Savannah Fanjul thinks about her step-sister Kayleigh Slusher,...

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Roisin Ariaz says a prayer at the memorial for Kayleigh Slusher outside the apartment building, Monday February 3, 2014 where the body of 3-year old little girls body was found dead, Saturday in Napa, Calif. " It's just so sad, she was an innocent," says Ariaz, a retired preschool teacher. The girl's mother Sara Krueger and her boyfriend Ryan Scott Warner have been arrested on suspicion of murder and assault in connection with the killing of Kayleigh.

An autopsy concluded that Kayleigh died of multiple blunt impact injuries to her head, torso and extremities due to child abuse and neglect, said District Attorney Gary Lieberstein.

Kayleigh's body was found Feb. 1 by Napa officers who had been summoned to Krueger's second-floor unit at 2060 Wilkins Ave. to do a welfare check, authorities said. The criminal complaint accuses the couple of killing Kayleigh on Jan. 30, the day after police had visited the apartment to check on the girl.

The couple left the home and were detained on Feb. 2 by BART police at the El Cerrito del Norte Station. They admitted to investigators that they hid the child's body in a suitcase inside a freezer for three days, according to court documents.

Police had been called several times to the couple's apartment to investigate disturbances, authorities said. But there had been no calls about Kayleigh, whose father is in prison, to the county agency in charge of protecting children from abuse.